C/C++ 中缀表达式转换成后缀表达式并求值

#include <stdio.h>
#include <math.h>
#include <stdlib.h>

#define STACK_INIT_SIZE 100
#define STACKINCREMENT 10

typedef struct{
char *base;
char *top;
int stacksize;
}SqStack1;

typedef struct{
double *base;
double *top;
int stacksize;
}SqStack2;

SqStack1 OPTR;
SqStack2 OPND;

double EvaluateExpression();
void CHAR_InitStack(SqStack1 &S);
void DOUBLE_InitStack(SqStack2 &S);
char CHAR_GetTop(SqStack1 S);
double DOUBLE_GetTop(SqStack2 S);
int CHAR_Push(SqStack1 &S , char e);
int DOUBLE_Push(SqStack2 &S , double e);
char CHAR_Pop(SqStack1 &S , char &e);
double DOUBLE_Pop(SqStack2 &S , double &e);
char Precede(char a,char b);
double Operate ( double d ,char e,double f);
int In(char c);

int main(void)
{
double result;
printf("*************************\n");
printf("*      表达式计算       *\n");
printf("*************************\n");
printf("请输入一组表达式(以#号结束):\n");
result = EvaluateExpression();
printf("\n\n计算结果是(结果保留两位小数):%.2f\n\n\n",result);
}

void CHAR_InitStack(SqStack1 &S)
{
S.base=(char *)malloc(STACK_INIT_SIZE * sizeof(char));
if(!S.base)exit(OVERFLOW);
S.top = S.base;
S.stacksize = STACK_INIT_SIZE;
}

void DOUBLE_InitStack(SqStack2 &S)
{
S.base=(double *)malloc(STACK_INIT_SIZE * sizeof(double));
if(!S.base)exit(OVERFLOW);
S.top = S.base;
S.stacksize = STACK_INIT_SIZE;
}

char CHAR_GetTop(SqStack1 S)
{
char e;
if(S.top == S.base) return -1;
e = *(S.top-1);
return e;
}

double DOUBLE_GetTop(SqStack2 S)
{
double e;
if(S.top == S.base) return -1;
e = *(S.top-1);
return e;
}

int CHAR_Push(SqStack1 &S , char e)
{
if(S.top - S.base >= S.stacksize)
{
S.base = (char *)realloc(S.base , (S.stacksize + STACKINCREMENT) * sizeof(char));
if(!S.base) exit(OVERFLOW);
S.top = S.base + S.stacksize;
S.stacksize += STACKINCREMENT;
}
*S.top++ = e;
return 1;
}

int DOUBLE_Push(SqStack2 &S , double e)
{
if(S.top - S.base >= S.stacksize)
{
S.base = (double *)realloc(S.base , (S.stacksize + STACKINCREMENT) * sizeof(double));
if(!S.base) exit(OVERFLOW);
S.top = S.base + S.stacksize;
S.stacksize += STACKINCREMENT;
}
*S.top++ = e;
return 1;
}

char CHAR_Pop(SqStack1 &S , char &e)
{
if(S.top == S.base)return -1;
e = * --S.top;
return e;
}

double DOUBLE_Pop(SqStack2 &S , double &e)
{
if(S.top == S.base)return -1;
e = * --S.top;
return e;
}

int In(char c)  // 判断是否为运算符
{
if ( c=='(' || c=='+' || c=='-' || c == '*' || c=='/' || c==')' || c=='#' || c=='^')
return 1;
else
return 0;
}

char Precede(char a,char b) //判断优先级
{
char op;
switch(a)
{
case '#':
if (b=='#')
op='=';
else op='<';
break;
case '+':
if (b=='*' || b=='/' || b=='('|| b=='^')
op='<';
else op='>';
break;
case '-':
if (b=='*' || b=='/' || b=='(' || b=='^')
op='<';
else op='>';
break;
case '*':
if (b=='(' || b=='^')
op='<';
else op='>';
break;
case '/':
if (b=='(' || b=='^')
op='<';
else op='>';
break;
case'^':
if(b=='(')
op='<';
else op='>';
break;
case '(':
if (b==')')
op='=';
else op='<';
break;
case ')':
op='>';
break;
}
return op;
}

double Operate( double d ,char e,double f) //计算
{
double g;
switch(e)
{
case '+':
g=d+f;
break;
case '-':
g=d-f;
break;
case '*':
g=d*f;
break;
case '/':
g=d/f;
break;
case '^':
g=pow(d,f);
break;
}
return g;
}

double EvaluateExpression()
{
char c=0,theta,x;
double a,b,number, n=0;
CHAR_InitStack (OPTR);
CHAR_Push (OPTR,'#');
DOUBLE_InitStack (OPND);
c = getchar();
printf("\n转化成后缀表达式是:");
while (c!='#'|| CHAR_GetTop(OPTR)!='#')
{
if(!In(c))
{
number=0;
while(!In(c))
{
if(c=='.')
break;
number = number*10 +(c-48);
c = getchar();
}
if(c=='.')
{
n=1;
while(!In(c = getchar()))
{
number = number +(c-48)*(double)pow(0.1 , n);
n++;
}
}
DOUBLE_Push (OPND,number);
printf("%.2f ",number);
}
else
switch (Precede(CHAR_GetTop(OPTR),c))
{
case '<':
CHAR_Push(OPTR , c);
c=getchar();
break;
case '=':
CHAR_Pop(OPTR , x);
c=getchar();
break;
case '>':
CHAR_Pop(OPTR , theta);
printf("%c ",theta);
DOUBLE_Pop(OPND , a);
DOUBLE_Pop(OPND , b);
DOUBLE_Push(OPND,Operate(b,theta,a));
break;
}
}
return (DOUBLE_GetTop(OPND));
}//int EvaluateExpression